Abstract : A transverse flow continous wave atomic iodine laser system uses a closed cycle fuel system to operate in a continuous mode. An elliptical pump cell having a Hg arc lampo cooled by deionized water irradiates with UV energy C3F7I gas to produce excited atomic iodine. A transverse flow section attached to the pump cell channels C3F7I gas into a laser cell where lasing occurs. The flow section has upstream and downstream flow cavities, triangular shaped, that channel the laser gas. A diffuser and flow straighteners are placed in these cavities to make velocity across the transverse laser axis as uniform as possible so as to produce very stable laser gain output.